Wumpus is a kernel library for generating 2D vector pictures,
its salient feature is portability due to no FFI dependencies.
It can generate PostScript (EPS) files and SVG files. The
generated PostScript code is plain [1] and reasonably
efficient as the use of stack operations, i.e gsave and
grestore, is minimized.

Pictures in Wumpus are made from paths and text labels.
Paths themselves are made from points. The usual affine
transformations (rotations, scaling, translations) can be
applied to geometric objects. Unlike PostScript there is no
notion of a current point, Wumpus builds pictures in a
coordinate-free style.

GENERAL DRAWBACKS...

For actually drawing pictures, diagrams, etc. Wumpus is very
low level. There is a supplemantary package wumpus-basic
available that helps create certain types of diagram, but it is
experimental - functionality is added an dropped between
releases.

Some of the design decisions made for wumpus-core are not
sophisticated (e.g. how attributes like colour are handled,
and how the bounding boxes of text labels are calculated), so
Wumpus might be limited compared to other systems. However,
the design permits a fairly simple implementation - which is
a priority. Text encoding an exception - I'm not sure how
reasonable the design is. The current implementation
appears okay for Latin 1 but may be inadequate for other
character sets, so I may have to revise it significantly.

\[1\] Because the output is simple, straight-line PostScript
code, it is possible to use GraphicsMagick or a similar tool
to convert Wumpus's EPS files to many other formats
(bitmaps).

Changelog:

23.0 to 0.30.0:

Substantial changes - the output machinery has been heavily
modified, the intention was to reduce the use of matrix
transformations in SVG output. Though this goal has not been
achieved, some code-size improvements in the SVG output have
been made.

The code generation monads have been changed - Wumpus no
longer uses a writer monad for code generation, but it will
keep the Wumpus name.

The Core.Colour module has been simplified to support just
one (new) type - RGBi, and the conversion type class
PSColour has been eliminated.

Core.Picture - the type of the frame function has been
changed to take a list of Primitives rather than a single
Primitive. The function frameMulti which previously
provided this functionality has been removed. SVG hyperlinks
are now supported for Primitives.

The default font size has been changed to 14 pt.

The Path datatype has been renamed PrimPath, likewise Ellipse
is now PrimEllispe and Label becomes PrimLabel.

Core.Geometry now longer defines an affine frame datatype.

Core.BoundingBox module changed significantly. The corner
functions (boundaryBottomLeft, etc.) have been removed,
along with the plane functions (leftPlane, etc.). Some
functions have been given more verbose names - corners is
now boundaryCorners, within is now withinBoundary and
union is now boundaryUnion.

Changed all functions in Core.FontSize to return PtSize
instead of a polymorphic type u (where u is an instance
of Fractional). To get to another unit type rather than
FontSize use an explicit conversion that scales the value
accordingly.

Added FromPtSize class constraints to various functions in
Core.Picture.